Implement the estimate done vs estimate undone progress bar

COS:

• Green is the sum of the estimate value for the completed stories, the line (unfilled section) is the sum of the estimate value for the incompleted stories
• Tooltip shows both estimate sums and %'s
• Put in expanded Epic information panel

Testing Notes
Q: How will this handle filtered issues?
A: Doesn't change

Q: What happens to the bar if there is no estimation statistic for the board?
A: There always is

Q: What if a non-story points estimate is chosen?
A: The bar should represent the completed % of whatever estimate statistic is used.

Q: What if there are no stories to estimate, or there's only 1?
A: If there are no stories it shows as completed (nothing left outstanding right?) If there are no stories estimated it shows as completed unless the estimation statistic is issue count. If there's one story with an estimate incompleted it shows as empty.

Q: What about the estimates on subtasks? Are those summed as well?
A: No. These are used only for remaining estimate.

Q: Does the bar update if an invalid estimate is entered?
A: No

Q: Does the bar update on estimate change of a story in the sprint?
A: You can't change an estimate of a story in a sprint once it's started. If it hasn't started then yes.

Q: Does the bar update on drag of a story into the sprint?
A: No, only on stories being completed or added into an epic.